Controlling system for reaction motors



Aug. 23, 1949. J w ETAL 2,479,888

CONTROLLING SYSTEM FOR REACTION MOTORS Filed July 6, 1943 3 Sheets-Sheet1 JRMES H. WYLD LOVELL LAWRENCE JR- I INVENTORJ ATTORNEY Aug. 23, 1949.J. H. WYLD ETAL 2,479,883

CONTROLLING SYSTEM FOR REACTION MOTORS Filed July 6, 1943 3 Sheets-Sheet2 O O 4 66 7 /3 O U 47 73 3 6 /6 JAHE5 H.WYLD LOVELL LAWRENCE JR.

INVENTORJ T RNEY Aug. 23, 1949. J. H. WYLD ET AL 2$479,388

CONTROLLING SYSTEM FOR REACTION MOTORS Filed July 6, 1945 S Sheets-Sheeta E I? Z6 '2 27 ox azw PEDIIC FIG -7 JAMES HWYLD LOVELL LAWRENCE .m.

I INVENTORS BY MW ATTO RN E! Patented Aug. 23, 1949 CONTROLLING SYSTEMFOR REACTION MOTORS James H. Wyld, Pompton Lakes, and Lovell Lawrence.Jr.. Paterson. N. J.. asslgnors to Reaction Motors Inc., Pompton Plains,N.

tion of New Jersey J., a corpora- Application July 6, i943, Serial No.493,670 18 Claims. (Cl. 60-353) The present invention relates tomechanism for starting and controlling the operation of jet reaction orrocket motors producing a useful propulsive thrust by the recoil actionof a high! velocity gas jet, particularly reaction motors actuated bythe continuous combustion in a chamber of two or more liquid propellantsfed under pressure to the motor from tanks; and it further relates todevices for ensuring a proper and safe sequence of controllingoperations, and to means for indicatin the operating conditions to apilot or operator at a point remote from the motor, and for transmittingcontrol impulses from said control points to the reaction motor.

In operating a reaction motor of the liquid propellant type, severalpreliminary operations are performed before the motor can be started.As-

suming that pressure-tank feed is used, the vent valves on top of thepropellant tanks are first closed, and gas under pressure is then fed tothe tanks until the proper working feed pressure is built up. To startthe motor the ignition device (such as a fuse or burner) is first turnedon, and the main fuel valves are immediately afterward opened to permitflow of propellant from the tanks to the motor. At the completion ofcombustion, the reaction motor unit is shut down by performing the aboveoperations in reverse order. It may also be necessary to vary the thrustover a wide range while the motor is working or to start and stop thelatter several times in rapid succession.

Undesirable or dangerous conditions may arise if the above operationsare not performed in cor rect order; thus, if the main propellant valvesare turned on before the ignitor burner, the combustion chamber of themotor may fill up with a 'liquid explosive mixture which will violentlyexplode when the ignitor is operated. Such accidents can be preventedeither by operating the starting equipment from an automatic controlwhich ensures a proper sequence of operations, or by providing suitableinterlocking mechanisms which prevent the operator from manipulating thecontrols in incorrect order.

One of the purposes of the present invention is to provide means forsuch automatic operation and/or interlocking of the controls of areaction motor, as will appear from a description of the invention.

A more specific object of the invention is to provide a starting controldevice for a reaction motor wherein an initial fiow of propellant fluidis fed to the motor and ignited, and in which in- 2 creased flow isprevented until ignition has been eifected.

A further object resides in the provision of automatic mechanism forvarying the ratio of propellant flow to prevent overheating of themotor.

A still further object is to provide means for automatically purging themotor of unburned propellant upon stoppage of the operation of themotor.

Another object of the invention is to provide a control system for areaction motor in which movement of a single operating lever will effectstarting, operating and stopping of the motor operation.

Other objects of the invention will be pointed out in the followingdescription and claims and illustrated in the accompanying drawings,which disclose, by way of example the principle of the invention and thebest mode, which has been contemplated, of applying that principle.

In the drawings:

Fig. 1 is a diagrammatic representation of a control system in which thefluid propellant is fed to the motor under gas pressure.

Fig. 2 is a detail of a modified form of ignition burner for the motor.

Fig. 3 is a plan detail of the operating lever mechanism.

Fig. 4 is a detail of a further modified form of ignition burner.

Fig. 5 is a detail of a modified form of main valve operating mechanism.

Fig. 6 is a diagrammatic representation of a modified system, whereinthe propellant is fed to the motor by pump pressure devices.

Fig. 7 is a detail of a modified form of pressure pump controllingmechanism.

A preferred form of the invention intended particularly for reactionmotors used as auxiliary power for aircraft is shown in Fig. 1.

All the motor operations are controlled .by the handle I attached tobellcrank 2. Handle l is provided with a spring latch 26 working on anotched quadrant 21, permitting handle I to be set to any desiredposition on quadrant 21 and thereafter locked in position. Bellcrank 2operates the hydraulic cylinder 3 through rod I. Displacement of thepiston in cylinder 3 pumps fluid through pipe '5, causing the piston ofthe receiver cylinder 6 to rise. The piston rod 1 acts on lever 8,causing the eccentric disk 9 to revolve. The eccentric 9 has aclose-fitting strap ill at tached to a connecting rod ll pivoted to acrosshead I 2 working in guides l3. As eccentric 9 revolves, thecrosshead I2 is moved up or down.

upon the lift of these The motion of crosshead I2 acting on crossarm I8determines the lift of the poppet valves I1 and I8. The stems of valvesI1 and I8 are provided with flexible metallic bellows I4, I5, whichpermit motion of the valve stems but prevent leakage. These valvescontrol the flow of the propellants from the pressure tanks I9 and 28 tothe reaction motor 2|. Tank or reservoir 28 contains a suitableinflammable fluid (such as gasoline) while tank or reservoir I9 containsa fluid oxidizin agent (such as liquid oxygen). When liquid oxygen orany similar volatile material is used as an oxidizer, tank I9 ispreferably provided with an outer jacket I41. The space between jacketI41 and tank I9 is evacuated or else packed with a heat insulatingmaterial, in order to insulate the tank from atmospheric heat andprevent evaporation of the oxygen.

Assuming a constant gas feed pressure in tanks I9 and 28, the rate ofpropellant feed, and thus the thrust of the reaction motor 2I will varywith the port area of valves I1 and I8, which depends valves;consequently, the setting of handle I will determine the motor thrust.

One form of reaction motor suited to the present method of control isshown in Fig. 1. It is of the self-cooled or regenerative type. Themotor consists of an inner combustion chamber II9, inside which thecombustion occurs. chamber I I9 is attached an expansion nozzle I28,through which the burning gases are ejected, thereby producing apropulsive thrust. To prevent overheating of the combustion chamber H9and nozzle I28 by the intensely hot gases, an ex- 1 T ternal coolingjacket I2I and bafiie I22 are provided. These are separated from chamberIIS and nozzle I28 by a narrow annular passage I23. One of the liquidpropellants is fed to the annular space outside bafiie I22, and flowsthrough passage I23, thereby cooling nozzle I28 and chamber H9. Thepropellant is thereby heated and partly vaporized, and escapes into theinterior of chamber II9 through a. ring of ports I24, mixing with theother propellant which is injected through ports I25 from manifold I48.The mixture is ignited by burner 52, as will be described later.

It is necessary to maintain a proper mixture proportion between the twopropellants, which is accomplished by making the ports of valves I1 andI8 different in size. It is often desirable to have different mixtureratios according to whether the reaction motor is operating at fulloutput or at reduced output. One method of accomplishing this is toprovide metering orifices or constrictions 22 in the propellant pipes.The sizes of these orifices are adjusted to produce a correct mixtureratio when the valves I1 and I8 are fully open, the pressure dropthrough these valves being negligible compared to that through theorifices 22. The port areas of valves I1 and I8 are proportioned so asto produce the proper mixture ratio when the valves are nearly closed.the effect of the orifices 22 being negligible for this flow condition.At intermediate valve settings the mixture ratio varies between thelimits set for the high-thrust and low-thrust conditions, depending onwhether the effect of valves I1 and I8 or that of orifices 22predominates.

It will be noted that the center of the eccentric disk 9 is so placed asto be nearly on "dead center when valves I1 and I8 are seated. Thisprovides a very powerful leverage in order to open the valves againstthe full tank pressure when 4 starting the motor, and also in order tocompress springs 24 when closing the valves. This arrangement alsoprovides a slower rate of lift when the valves are slightly open thanwhen they are open wide, thereby compensating for the disproportionatelylarge flow rate at small openings (caused by the large pressure dropbetween the tanks and reaction motor when the latter is operating atreduced output).

Besides valves I1 and I8 and orifices 22, check valves 23 are providedin the propellant conduits or lines, in order to prevent combustiblemixture from flowing back into the pipes or tanks if temporary pressuresurges occur in motor 2I.

Since valves I1 and I8 act as shut-off valves as well as throttles, itis necessary for them to close very positively. For this reason, springs24 are provided which keep the crossarm I5 pressed against the stops 25attached to the stems of valves I1 and I8. These valves are adjusted tocontact their seats slightly before crosshead I2 reaches the end of itsstroke. Thereafter, the further downward motion of crosshead I2 causescrossarm I5 to compress springs 24, thus firmly holding valves I1 and I8down on their seats. This arrangement ensures that both valves I1 and I8will seat positively, regardless of whether or not one valve seats aheadof the other. Furthermore, as soon as both valves I1 and I8 are clear oftheir seats, they will lift or drop together in a definite positionrelative to each other, determined by stops 25. Stops 25 are adjustablealong the valve stems by means of screws, nuts, or other devices, so asto permit proper adjustment of the seating of valves I1 and I8.

In order to indicate the thrust of the motor 2| to the pilot or operatorof control handle I, a pressure gage 28 mounted near handle I isconnected to the combustion chamber of motor 2I by a tube 29. It hasbeen found that the thrust produced by a given reaction motor bears adeflnite relation to the pressure in the combustion chamber. Gage 28 canthus be calibrated to indicate motor thrust directly.

It has previously been mentioned that it is necessary to close thepropellant tank vents, charge the tanks with pressure and start theignition device before turning on the motor. These operations arecarried out by an auxiliary control, operated by handle I. The bellcrank2 carries a pawl 38, which engages a ratchet wheel 3| when the handle Iis moved into its extreme lefthand (or closed) position (indicated bydotted lines). The ratchet 3I revolves a rotary switch 32, whichalternately closes and opens an electrical circuit on successive strokesof pawl 38. The switch 32 is in series with a safety switch 33 andbattery 34.

The control handle I and the lever 8 are provided with springs 35 and36, whose tension is adjusted so as to maintain the levers I and 8 in aneutral position in which valves I1 and I8 are fully closed, and thepiston of cylinder 8 is fully down, but pawl 38 does not engage hatchet3|. To turn the ratchet, it is necessary to push handle I to the leftagainst the pressure of spring 35, which is a short, stiff compressionspring which comes in contact with handle I only when the latter ispushed to the extreme left, but which releases itself from handle I whenthe latter is pushed to the right.

The leftward motion of handle I also synchronizes cylinders 3 and 6 byopening a bypass valve 31 which temporarily connects pipe 5 with the oilreservoir 38, permitting oil to leak in or out of the pipe to compensatefor any thermal expansion or leakage of the oil. This result can also beaccomplished by means of a port 38 in the wall of the cylinder 3. Thisport is overrun by the piston or cylinder 3 when handle I is pushed tothe limit of its stroke, allowing cylinder 3 to communicate directlywith reservoir 38. It will be noted that leakage or breakage of pipewill cause spring 36 to close valves I1 and I8, thereby automaticallyshutting of! motor 2!.

Assuming that switch 32 is open and safety switch 33 is closed, pressinghandle I to the extreme left causes pawl 3|) and ratchet 3| to revolveswitch 32, closing the circuit through battery 34. This causes currentto flow through the solenoids of valves 40, M, 42, 43, 44 and also theheater coil 45 and vibrator-type spark coil 46. The valves 40 and M thenclose, shutting oil the venting between the tanks and the external air.The valve 44 opens, supplying high pressure nitrogen gas (or othersuitable inert gas, such as helium) from tank 41 through reducing valve48, in which the pressure is reduced to a value suitable for the tankfeed pressure. The gas is then fed from valve 48 through check valves 49to the tanks I3 and 20. Simultaneously, valves 42 and 43 are opened,causing propellants to flow from tanks I9 and 28 through valves 42 and43, metering orifices 50, and check valves 5| to the ignition burner 52,attached to reaction motor 2|. The propellants mix in the burner 52 andare ignited by the spark plug 53 operated by spark coil 46. It will benoted that the hydrocarbon propellant from tank 20 flows through theheating coil 45, which is electrically insulated from the rest of thepiping by insulating bushings 54. Coil 45 is made of fine bore tubing ofhigh electrical resistivity heated by the passage of current frombattery 34. By thus combining the electric heating element with theheat-transfer surface of the coil, instantaneous heating andvaporization of the propellant is secured.

If liquid oxygen is used as the oxidizing propellant (as is frequentlythe case), it is found in practice that the small amount of oxygenrequired to operate the burner will automatically evaporate from liquidto gas in passing through the comparatively warm pipes between tank I9and burner 52, arriving in the burner as oxygen gas. It is foundexperimentally that if both propellants are fed to the burner as vapors,as described above, the ease and reliability of igniting and burningthem are improved.

A preferred construction of the ignition burner 52 is shown in detail inFig. 2. The burner chamber I38 provided with air-cooling fins I38 screwsinto the end of the oxygen manifold I48 and clamps down the extensiontube MI. The mixer head I42 screws into the opposite end of burnerchamber I38. Mixer I 42 contains a central jet tube I43, through whichoxygen gas is injected into chamber I38. Tube I43 is surrounded by anannular space I44, slightly constricted at its right hand or exit end,into which hydrocarbon vapor or liquid is fed from pipe I45. Theconstriction at the end of space I44 together with the tapered end oftube I43 causes the hydrocarbon jet from space I44 to impinge on theoxygen jet from tube I43, resulting in a highly atomized oxy-hydrocarbonmixture, which is ignited by the spark plug 53 and passes out throughtube I4I into the combustion chamber II9 of reaction motor 2I, producingan intense flame which ignites the combustible mixture in chamber II! assoon as valves I1 and II are turned on. A thimble I46 is screwed intochamber I33 and contains a thermocouple 68, which is used as a, safetythermostatic interlock, as will be described later.

The burner chamber I38 is preferably composed of a metal of high thermalconductivity such as aluminum alloy or copper, to assist in dissipatingthe heat absorbed by the chamber walls. The extension tube I should beof a metal resistant to high temperatures to resist the action of theflame when first starting the burner. Once the main motor 2| is turnedon, tube I is cooled by the flow of oxidizer through manifold I48 andports I25.

Although a regenerative type of reaction motor is described inconnection with this ignition burner and control apparatus in thepresent specification for purposes of illustration, the same burner andcontrol devices can also be applied to any other type ofcontinuous-combustion reaction motor, r quiring only minor changes inconstruction which do not affect the essential principles involved.

It is evidently dangerous to feed propellants from the main valves I1and I8 into the reaction motor 2I before the burner 52 is properlylighted, since this may lead to an accumulation of unburned fuel in themotor chamber, causing a violent explosion when the ignition finallytakes efiect. It is also undesirable to turn on the motor until fullfeed pressure has been built up in tanks I8 and 20. To prevent suchpremature operation of the motor, a locking bolt 54 (see Figs. 1 and 3)is provided attached to an iron rod 55a and the spring 55. The frontface of bolt 54 is inclined (see Fig. 3) and consequently permits handleI to be moved past the bolt towards the left in order to start themotor, but prevents the operator from returning handle I to the rightand opening valves I1 and I8 until bolt 54 is withdrawn, which isaccomplished at the proper time by the solenoid 51. This solenoid 51 isin series with battery 34, contacts of sensitive relay 58, and pressureswitches 58. Relay 58 is energized by the action of the thermocouple 68attached to burner 52, as soon as the burner is heated by the beginningof combustion within it.

An alternative method of providing for releasing a lever I after burner52 is lighted is shown in Fig. 4. This device consists of bulb 55,flexible metal bellows I84, and insulated contact I85. Bulb 55 containsa volatile liquid which is evaporated by the heat of burner 52. Theresulting vapor pressure in bellows I84 causes the latter to expand,closing contact I05, which is in series with switches 59 and solenoid51. Switches 58 are adjusted to close as soon as the tank pressuresreach the proper value. Solenoid 51 then operates, withdrawing bolt 54and permitting the operator to move handle I to the right and start themotor. The operator is notified of the operation of solenoid 51 by thesignal light 62 connected in parallel with solenoid 51. A hand knob 5|(Fig. 3) permits bolt 54 to be released manually for testing theequipment or to release the solenoid in case of sticking.

It is found in practice that the operation of the ignition burner 52results in a considerable gas pressure within the combustion space ofchamber I38. It is also apparent that the operation of burner 52 will beindicated to the operator by a rise in the reading of pressure gage 28,

the latter being connected to burner 52 as shown in Figs. 1, 2 and 4.

.leased and returns a ,under the action of/ spring 35, operating pawl Tostop the motor, the handle I is moved to the left to the full lineposition of Fig. 1 and valves I1 and I8 close. The burner 52 continuesto operate, and pressure is left on in tanks l9 and 20. Therefore, themotor can be restarted simply by moving handle I back to the right andreopening the propellant valves I1 and I8. To shut down the equipmentcompletely, handle I is moved to the extreme left against the pressureof spring permitt ng pawl 38 to engage the next tooth on ratchet 3|.Handle I is then rehort distance to the right 38 and ratchet 3| andopening the circuit through switch 32, thus venting the tanks I9 and 20through valves and 4|, which open automatically when the electriccurrent in their solenoids is cut off. Valve 4| is connected to themotor 2| through pipe 83 and check valve 64, thus causing the pressuregas from tank 28 to blow off through motor 2| and purge out anylingering explosive charge in the motor chamber.

The opening of switch 32 also closes the valve 44, shutting off the flowof pressure gas from tank 41. Simultaneously, the flow of propellants toburner'52 is stopped by the closing of valves 42 and 43, and heater andspark coil 48 are also shut off.

The switch 32 can be operated manually by means of knob 65. Safetyswitch 33 can also be used to open the circuit and return the variouscontrols to the stopped position.

When operating reaction motor 2| for prolonged periods at reducedoutput, there is sometimes a tendency for the motor to overheat, owingto the reduced supply of coolant to space I23. Valves I1 and I8 areadjusted to supply a "rich mixture (that is, a high ratio of hydrocarbonto oxidizer) atlower output, to compensate for this effect. It is alsodesirable to have a safety device which automatically supplies morecoolant if the motor 2| becomes unduly hot. This may be accomplished bythe use of a thermocouple I26 attached to the liner chamber H9 or someother highly heated part of the motor 2|. Excessive temperature causesthermocouple I26 to close the sensitive relay I21, which thereby opensthe solenoid by-pass valve I28, permitting the hydrocarbon propellant tofiow directly from tank 28 to motor 2|, thus increasing the flow ofcoolant. As the supply of oxidizer from tank I9 is not affected by thisoperation, the motor thrust will not be appreciably increased.

Experience has shown that it is undesirable to permit the liquid levelin either tank I9 or tank 2|) to decrease below a certain limit whilemotor 2 I is in operation, since there is then a tendency to drawbubbles of gas into the tank outlets, resulting in objectionableoscillations or detonations in the motor combusion. To obviate such acondition. floats I29 and I38 are provided. operating switch elementsI3I and I32 installed in the walls of tanks I9 and 20. Switches I 3| andI32 are connected in series, and are normally closed when the floats I29and I38 are raised by the liouid in the tanks. One side of switches I3Iand I32 is connected to switch 32. The other side leads to the windingsof solenoid valves I33 and I34 (which are held open when the current ison, but other-wise close automatically), and thence back to the returnlead to battery 34. Any fall in liquid level below the level of thefloat in either tank I9 or 28 will thus cause one of the switches I3Iand I32 to open, thereby closing the shut-oil valves I33 and I34 andstopping the motor. As the valves are in series with switches 32 and 33,they will also be closed by the opening of either of these switches, orby any other interruption in the electric current supply, thus providingan additional safety feature. Since valves I1 and I8 are purelymechanical in either operation, they enable the motor to be shut oflentirely independently of the electrical valves I33 and I34. Conversely,valves I33 and I34 act as safety devices in cases of failure of thethrottle valves I1 and I8.

It is also desirable in certain cases to apply a pneumatic servomechanism to cylinder 8, actuated by auxiliary nitrogen gas pressure(see Fig. 5). Handle moves bellcrank 2 and the piston of cylinder 3,thus moving the piston of cylinder 8 by the hydraulic pressure in pipe5. The piston rod I operates a slide valve 86, moving in the valve chest61. Pressure is supplied to the center of valve chest 61 through aflexible tube 68 leading to the reducing valve 48. Motion of valve 85upward uncovers the port 18, causing gas pressure to be fed to the upperend of cylinder 1| while the lower end of the cylinder is permitted toexhaust through port 69 and the open end of valve chest 61. The cylinder1| then slides upward on the rod 13 (piston 12 and rod 13 remainingfixed). This action revolves the eccentric 9 by means of rod 14 andlever 8, thus operating crosshead I2 which controls the main propellantvalves, as described previously. The motion of cylinder 1| closes theinlet port 18, stopping further motion of the cylinder 1| till valve 68is moved to a new position. The motion of cylinder 1| thus closelyfollows that of valve 68, and hence of handle I. Handle I, however, needsupply only enough force to actuate valve 68, instead of revolvingeccentric 9 directly. This arrangement is desirable if valves I1 and I8are of such a size as to require an ob- Jectionably large control forceif operated directly from cylinder 6. It should also be noted thatvalves I1 and I8 cannot be opened until pressure is fed to the reducingvalve 48 by the opening of valve 44, since the compression spring 36main- 45 tains eccentric 9 in the closed position until pressure issupplied to cylinder 1|. Since valve 48 also supplies tanks I3 and 2|),valves I1 and I8 will-not open when pressure is not being fed to thesetanks, thus providing a further safety 50 feature.

In cases where the eccentric 9 and handle I are not too far apart, thehydraulic system (comprising cylinders 3 and 8 and pipe 5, together withoil reservoir 38 and valve 31) may be dispensed with, and the handle Ican be connected to eccentric 9 by a torque shaft, a push rod, flexiblecables, or other direct mechanical connection. The hydraulic system,however, affords a more conven lent, flexible, and readily installedcontrol system 80 if the reaction motor equipment is mounted aconsiderable distance away from the pilot, as is usually the case.

For certain applications of reaction motors, it is advantageous to feedthe propellants to the reaction motor by means of a pump system, thetanks being maintained at atmospheric pressure. This is particularlyuseful on military aircraft, since the propellant tanks and nitrogen gastank used in a gas-pressure feed system offer a very vulnerable targetto enemy gunfire during the period in which the reaction motor is inoperation, with full pressure in all the tanks. On the other hand, apump system requires only a few parts of the system to operate at highpressure and a violent explosion or fire is very unlikely in ease ofdamage to the equipment by gunfire or otherwise. The use of pumps alsoenables higher motor pressures to be used without an unreasonableincrease in weight, since it is only necessary to increase the weight ofthe motor, pumps, and drive motor to reach high pressures with pumpfeed, while with gas pressure feed it is necessary to increase theweight of the whole tank system. The use of high motor pressure resultsin greater thermal efliciency, as is well known in the prior art ofreaction motor design. An advantageous method of pumpingthe propellantsto the motor is the use of centrifugal pumps or else so-called rotarypumps (such as gear pumps or screw pumps) operated at high rotationalspeed, and driven by a small turbine operated by the gas pressure in thereaction motor combustion chamher. A control system suitable for such aninstallation is shown in Fig. 6.

Referring to Fig. 6, the propellants are contained in tanks I9 and 20,which are of much lighter construction than the corresponding tanks usedin the previously described gas-pressure feed system, since they aremaintained at atmospheric pressure at all times. The filling caps 14 ontop of the tanks are provided with check valves 15, which are soadjusted as to permit atmospheric air to flow into the tank readily, butto flow out only slowly. In this way, the tank contents are preventedfrom spilling out owing to oscillations or vibration of the tank, whileat the same time the outflow of the propellants through the bottomconnections will not cause a partial vacuum which would interfere withthe flow. The propellants are fed to the motor by pumps 16 and 11, whichmay conveniently be centrifugal r positive-displacement rotary pumps, ormulti-cylinder reciprocating pumps. If the propellant in tank I9 isliquid oxygen or other cold and highly volatile fluid, the pump 16 mayadvantageously be placed inside tank I9 mounted on a removable flangedplate 18. In this way, the pump 19 is brought to the same temperature asthe propellant before being put in operation, avoiding distortion of theparts by thermal contraction and preventing frosting-up of the pump,since it is surrounded by the propellant. The pump drive shaft 19 passesthrough a stufling box 82, which is mounted on an extension tube 80 withradiating fins 8| which absorb heat from the atmosphere and prevent thepacking in stufling box 82 from freezing.

Pumps 16 and 11 are driven by the worm wheel 93, which in turn is drivenby worm 84 on shaft 85. When friction clutch 86 is engaged by theoperation of shifter fork 81 by solenoid 88, shaft 85 is connected withturbine wheel 99, which is revolved by a gas jet escaping from nozzle90. The necessary gas pressure is furnished by the reaction motor 2|,through the pipe 9|; the gas flows through the tubes 92 of intercooler93, which is cooled by the fiow of propellant from pump 11 to reactionmotor 2| through jacket of intercooler 93. This arrangement is providedto cool the intensely hot motor gas, which would otherwise damage theblading of the turbine 89. Further cooling of the gas is provided by thedesuperheater tube I 09, which has a constricted throat I01 into whichopens a jet tube I08 connected to a small water tank I09. The clearancespace of tank- I09 is connected to chamber IIO ahead of throat I01. Theflow of gas through throat I01 sucks water from tank I09 through jetI08, in the form of flne spray, which rapidly vaporizes into steam, thuscooling the gas from pipe 9| and also increasing the volume of gas.

The speed of turbine 89 is regulated by the throttle valve 94, which iscontrolled through bellcrank 91 by the centrifugal governor 95 driven byreduction gears I02. Governor 95 throttles down the gas supply if thespeed of the pumps becomes excessive, maintaining the speed at adefinite value determined by the tension of compression spring 99,.whichopposes the action of the governor flyweights. The tension of spring 96can be varied by the motion of the piston of hydraulic cylinder 9. Thehydraulic pressure operating cylinder 5 is supplied through pipe 5 fromcylinder 3, the piston of which is moved by handle I and bellcrank 2.The position of handle I thus controls the motor thrust by regulatingthe setting of governor spring 96, and thus determining the speed ofturbine 89 and pumps 16 and 11. The latch 29 and sector 21 maintainhandle I in whatever position it is set.

It is necessary to provide an auxiliary source of power for starting theturbine and pumps before pressure begins to build up in the reactionmotor 2|. This is accomplished by bringing the turbine wheel 89 up to a,very high speed with friction clutch 89 disengaged and then engagingclutch 86, causing wheel 89 to rotate pumps 16 and 11 by its inertia orflywheel effect. The propellants are thus pumped into the reaction motor2|, where they are ignited by burner 52 and rapidly build up pressurewhich thereafter maintains turbine 89 in operation. The turbine wheel 89is brought up to speed by the electric starting motor 99, which revolveswheel 89 through the speed-increasing gears 99 and the overruning clutchI00. (Clutch I00 is shown diagrammatically as a jaw clutch, but inpractice it preferably takes the form of a wedging-roller clutch orother suitable friction device which looks the clutch if torque isapplied in one direction but loosens it if the torque reverses.)

A centrifugal switch I 0| is operated by governor 95 through bellcrank91. The switch IOI has two separate sets of contacts. The left hand setis in circuit with motor 99, shutting off the electric current to motor98 whenever the speed of wheel 99 exceeds a certain maximum determinedby the governor spring 96. The speed of wheel 89 is thus prevented frombecoming excessive while running the wheel up to speed.

To start up the motor, handle I is pushed past its neutral position,against the pressure of spring 35, to the extreme left-hand positionindicated in dotted lines. This actuates the synchronizing valve 31,thus synchronizing the cylinders 3 and 6 in the manner previouslydescribed. In addition, bellcrank 2 closes the upper contact of switchII2, thus energizing the motor 98 and revolving the turbine wheel 89.After the latter reaches a speed determined by the setting of governor95 and switch IOI, its revolution rate remains constant. The switch II2also supplies current to the left-hand half of the winding of relay II3,which closes the circuit through the solenoid valves 42 and 43. Theopening of valve 42 permits oxygen gas from pressure tank H4 andreducing valve II5 to flow to burner 52, while valve 43 similarly feedspropane, hydrogen, or other inflammable gas from pressure tank H6 andreducing valve 1. The gases mix in burner 52 and are ignited by sparkplug 53 actuated by spark coil 49 shunted across the solenoids of valves42 and 43.

When the ignition burner is properly lighted, the relay 58 is closed bythe action of thermocouple 50 attached to burner 52 (or by someequivalent thermostatic control). The contacts of relay 58 are in serieswith the right hand pair of contacts of the governor switch IN. Thelatter are arranged to close at a governor speed slightly below thatwhich opens the left-hand pair of contacts, so that when the wheel 68 isrunning at its rated starting speed the righthand contacts of switchIIlI remain continuously closed. If at the same time relay 58 is closed,the circuit is completed through solenoid 51, withdrawing the safetybolt 54. At the same time, the signal light 62 indicates to the operatorthat wheel 89 is up to full speed and burner 52 is lighted, and that thepumps 16 and 11 can now be started.

Handle I is now moved to the right (as indicated by the right handdotted lines) This opens the circuit through the upper contacts ofswitch H2, thus shutting off the starting motor 88. The wheel 89continues to revolve owing to its momentum, while the over-runningclutch I88 effectively disconnects motor 98 from wheel 88. The motion ofhandle I then closes the lower contacts of switch H2, energizing thesolenoid 88 and engaging clutch 86, thus starting pumps I6 and H, whichbegin to feed the propellants to the motor 2|, where they are ignited byburner 52. The motor II is then in full operation, and is thereaftercontrolled by governor 85, as previously described.

It will be noted that the operation of moving switch H2 from thestarting to the running position shifts the current flow in relay H3from the left half of the winding to the right half. While handle I ispassing momentarily through its neutral or "ofi position, both contactsof switch H2 are open and there is no current in the coil of relay H3.To prevent the relay H3 from momentarily opening and thus shutting offburner 52, a copper slug or short-circuited winding H8 is provided,whose self-inductance causes a delay in the opening of relay H3 untilthe circuit is reclosed through switch H2. An equivalent delay device(such as a dashpot) may replace winding H8.

To shut off the motor 2|, the handle I is returned to its neutralposition. This opens all the circuits, thus shutting off the igniterburner 52 and spark coil 46, and also opening clutch 86, stopping thepumps 16 and I1 and shutting off motor 2|.

Spring-loaded check valves I83 and I I I are provided in the fuel linesbetween tanks I9, 28 and the motor 2|. These valves are so adjusted asto remain shut under the hydrostatic head caused by the fuel in thetanks, but they open freely under the feed pressure developed by thepumps. The purpose of these valves is to prevent fuel from leakingthrough the pumps I6 and 11 into the motor 2I while the pumps aredisconnected from the turbine wheel 89.

An alternate method for starting pumps 16 and H which is particularlysuitable for centrifugal pumps is shown in Fig. 'l. The friction clutch86 is replaced by a permanently engaged, spring-loaded friction clutchI31, which is adjusted to slip if the torque exceeds a certain maximum,in order to protect the transmission shafts and gearing againstexcessive shocks resulting from variations in the pumping pressure,owing to changes in the combustion rate in the motor or other causes.Check valves I83 and III are replaced by the solenoid valves I35 andI36, which are connected to the lower contacts of switch I I2, andconsequently are opened when handle I is moved to the right into theoperating position. When starting the pump turbine 89, the pumps I6 and11 (which are of the centrifugal type) revolve with wheel 89, producinga pressure head in the pipes but delivering no fluid until valves I35and I36 are subsequently opened when handle I is moved to the startingposition. If the pumps 18 and I1 are of the positive-displacement type,valves I35 and I36 should be installed at the inlets to pumps I6 and 11(instead of the exhausts, as shown in Fig.7). In this case the pumprotors run dry until the valves I35 and I36 are opened. v

When high-speed centrifugal pumps are used, the gears 83 and 84 may bedispensed with, and the shaft 85 connected directly to shaft 19. Thepumps I6 and I1 then run at the same speed as turbine 89.

While there have been shown and described and pointed out thefundamental novel features of the invention as applied to a singlemodification, it will be understood that various omissions andsubstitutions and changes in the form and details of the deviceillustrated and in its operation may be made by those skilled in the artwithout departing from the spirit of the invention. It is the intentiontherefore to be limited only as indicated by the scope of the followingclaims.

What is claimed is:

1. In a system of the class described, a reaction motor having a maincombustion chamber and a firing chamber, a pair of reservoirs eachcontaining a liquid propellant, means for creating pressure within saidreservoir, pressure responsive means for each reservoir, a conduitbetween each reservoir and said combustion chamber, a further conduitbetween each reservoir and said firing chamber, a normally closed valvein each conduit, devices for causing opening of the valves in the firingchamber conduits and for concurrently rendering said pressure creatingmeans effective, further devices for opening the valves in thecombustion chamber conduits to enable propellant to flow therethrough,said first and second named devices being operable in succession, anignition device in said firing chamber operative to ignite thepropellants in said firing chamber, and means responsive jointly to theheat of combustion in said firing chamber and to said pressureresponsive means, for controlling the operation of said further devices.

2. In a system of the class described, a reaction motor having acombustion chamber, a pair of reservoirs each containing a liouidpropellant, means for creating pressure within said reservoir, pressureresponsive means for each reservoir, a main conduit between eachreservoir and said combustion chamber, an auxiliary conduit between eachreservoir and said combustion chamber, a normally closed valve in eachconduit, devices for causing opening of the valves in the auxiliaryconduits and for concurrently rendering said pressure creating meanseffective, further devices for opening the valves in the main conduits,said first and second named devices being operable in succession, anignition device in said combustion chamber operative to ignite thepropellants fed to the chamber through said auxiliary conduits, andmeans responsive jointly to the heat 'of combustion of said ignitedpropellants and to said pressure responsive means for controlling theoperation of said further devices.

3. In a system of the class described, a reaction motor having acombustion chamber. a reservoir containing a liquid propellant, meansfor creating pressure within said reservoir, pressure responsive meansfor the reservoir, 8. main conduit and an auxiliary conduit between saidreservoir and said combustion chamber, a normally closed valve in eachconduit, means for opening the valve in the auxiliary conduit to feedpropellant to said chamber, and for concurrently rendering said pressurecreating means effective, further means for opening the valve in themain conduit, said first and second named means being operable insuccession, an ignition device in said combustion chamber operative toignite the propellant fed to the chamber through said auxiliary conduit,and means responsive jointly to the heat of combustion of said ignitedpropellant and to said pressure responsive means for controlling theoperation of said further means.

4. In a system of the class described, a reaction motor having acombustion chamber, a reservoir containing a liquid propellant, meansfor creating pressure within said reservoir, pressure re-- sponsivemeans for the reservoir, a main conduit and an auxiliary conduit betweensaid reservoir and said combustion chamber, means for causing propellantto flow from the reservoir to said chamber through said auxiliaryconduit and for concurrently rendering said pressure creating meansefiective, an ignition device in said combustion chamber operative toignite the propellant fed thereto, normally ineffective operating meansfor causing propellant. to flow from the reservoir to the chamberthrough said main conduit, and means rendered effective upon theoccurrence of combustion in said chamber and the action of said pressureresponsive means for rendering said operating means effective.

5. In a system of the class described, a reaction motor having acombustion chamber, a reservoir containing liquid propellant, a conduitbetween said chamber and reservoir, a valve in said conduit, means forcreating pressure in said reservoir, a device for concurrently openingsaid valve and rendering said pressure creating means effective to feedpropellant under pressure to said chamber, means for causing combustionof the propellant in said chamber, normally ineffective operating meansfor causing feeding of additional propellant to said chamber, meansresponsive to the pressure created in said reservoir, temperatureresponsive means in said chamber, and means jointly controlled by saidtemperature responsive means and by said pressure responsive means forrendering said operating means effective. 6. In a system of the classdescribed, a reaction motor having a combustion chamber, a reservoircontaining liquid propellant, a conduit between said chamber andreservoir, a valve in said conduit, means for creating pressure in saidreservoir, a device for concurrently opening said valve and renderingsaid pressure creating means effective to feed propellant under pressureto said chamber, means for causing combustion of the propellant in saidchamber, normally inefi'ective means for controlling the feeding ofadditional propellant to said chamber and means responsive jointly tothe heat of combustion in said chamber and to the pressure in saidreservoir for rendering said normally ineflective means eifective.

7. In a control system of the class described, a reservoir containingliquid propellant, a reaction motor having a firing chamber and acombustion chamber, means for creating pressure in said reservoir, amain conduit between said reservoir and said combustion chamber, anauxiliary conduit between said reservoir and said firing chamber,ignition means in said flrlng chamber, a control lever movable from aneutral position to a starting position and then to an operatingposition, means normally preventing movement to said operating position,means concurrently controlled by the lever when moved to its startingposition for rendering said pressure creating means and said ignitionmeans efiective and for causing propellant to flow through saidauxiliary conduit, whereby combustion will take place in the chambers ofsaid motor, means for maintaining said last named means continuouslyefiective, means responsive to said heat of combustion for disablingsaid preventing means whereby said lever may be moved to its operatingposition, and means controlled by the lever when moved to its operatingposition for causing propellant to feed to the combustion chamberthrough said main conduits, the heat generated by the propellant fedthrough said auxiliary conduit causing combustion of the propellantsubsequently fed through the main conduit.

8. The invention set forth in claim 7 in which movement of the leverfrom its operating position back to its neutral position will operatethe last named means to disable feeding of propellant through said mainconduit and in which further means is provided and responsive a secondmovement of the lever to its starting position to disable feeding ofpropellant through said auxiliary conduit.

9. In a control system of the class described, a reservoir containingliquid propellant, a reaction motor having a firing chamber and acombustion chamber, means for creating pressure in said reservoir, amain conduit between said reservoir and said combustion chamber, anauxiliary conduit between said reservoir and said firing chamber,ignition means in said firing chamber, a control lever movable from aneutral position to a starting position and then to an operatingposition, means normally preventing movement to said operating position,means controlled by the lever when moved to its starting position forrendering said pressure creating means and said ignition means effectiveand for causing propellant to flow through said auxiliary conduitwhereby combustion will take place in the chamber of said motor, saidlast named means being controlled by the lever upon movement of thelever from its starting position to its neutral position and then backto its starting position to disable the pressure creating, ignition andpropellant flow means.

10. The invention set forth in claim 7 in which the pressure creatingmeans comprises means for introducing gas under pressure into saidreservoir, and means controlled by the lever upon movement of the leverfrom its operating position back to its neutral position for causing thegas in said reservoir to be directed into the combustion chamber topurge the same of propellant.

11. In a control system for a reaction motor, a reservoir containingliquid propellant, a reaction motor having a combustion chamber, meansfor creating pressure in said reservoir, 8. main conduit between saidreservoir and said chamber, an auxiliary conduit between said reservoirand said chamber, ignition means in said chamber, a control deviceadjustable to represent neutral, starting and operating conditions, insuccessive order, means normally preventing adjustment thereof torepresent the operating condition, means concurrently controlled by saidcontrol device when adjusted to represent the starting condition forrendering said pressure creating means and said ignition means effectiveand for causing propellant to flow through said auxiliary conduit,whereby combustion will take place in the chamber of said motor, meansfor maintaining said last named means continuously effective, meanseffective upon the occurrence of combustion in said chamber fordisabling said preventing means whereby said control device may beadjusted to represent the operating condition, and means controlled bythe device when so adjusted for causing propellant to feed to thechamber through said main conduit.

12. In a control system for a reaction motor, a reservoir containingliquid propellant, a. reaction motor having a combustion chamber, meansfor creating pressure in said reservoir, ignition means for ignitingpropellant in said chamber, a control device adjustable to represent aneutral and a starting condition, means controlled by said controldevice when adjusted to represent the starting condition for renderingsaid pressure creating means and said ignition means effective and forcausing propellant to flow from said reservoir to said combustionchamber whereby combustion will take place in the chamber of said motor,means for disabling said last named means, and means effective upon saiddisabling for venting the created pressure in said reservoir throughsaid combustion chamber to purge the same.

13. In a control system for a reaction motor, a reservoir containing aliquid propellant, a' reaction motor having a combustion chamber, meansfor creating pressure in said reservoir, ignition means for ignitingpropellant in said chamber, a control device adjustable to represent aneutral and a starting condition, electrical means controlled by saidcontrol device when adjusted to represent the starting condition forrendering said pressure creating and said ignition means efiective andfor causing propellant to flow from said reservoir to said combustionchamber, which combustion will take place in the chamber of said motor,means effective upon failure of current in said electrical means fordisabling said ignition and flow means, and means responsive upon suchfailure of current for directing the created pressure through thecombustion chamber to purge the same.

14. In a control system for a reaction motor, a reservoir containing apropellant, a reaction motor having a combustion chamber, a source ofgas under pressure, a control device adjustable to represent a neutraland a starting condition, means controlled by said device when adjustedto represent the starting condition for causing propellant to flow fromthe reservoir to the combustion chamber, means for causing interruptionof said flow, and means controlled by said interrupting means upon saidinterruption for directing gas from said pressuresource through thecombustion'chamber to purge the same.

15. In a control system for a reaction motor, a reservoir containing apropellant, a reaction motor having a combustion chamber, a source 01'gas under pressure, operator controlled means for causing propellant toflow from the reservoir to said chamber and for igniting said propellantin the chamber, means at the will of the operator for interrupting saidflow, and means controlled by said interrupting means for directing gasfrom said pressure source through the chamber to purge the same.

16. In a system of the class described, a reaction motor having acombustion chamber, a normally ineffective fuel pumping mechanism forpumping fuel to said chamber, separate means for feeding a charge offuel to the combustion chamber and igniting said charge, means effectivewhen said charge is ignited for rendering the pumping mechanismeffective, and further means effective when the charge is ignited forcausing the products of the combustion to operate the pumping mechanism.

17. The invention set forth in claim 16 in which the last named meanscomprises a turbine driven by the gases of combustion and includesdevices for adding water to the gases before they operate the turbine.

18. In a system of the class'described, a reaction motor having acombustion chamber, a fuel reservoir, pumping mechanism for pumping fuelfrom the reservoir to the combustion cham. her, a driving turbine forsaid pumping mechanism, connecting means therebetween, normallyinefiective operating means therefor, control means for driving theturbine, sending a charge of fuel to the chamber and igniting the same,means responsive to the heat of combustion of the ignited propellant,means controlled jointly by the turbine when-it reaches a predeterminedspeed and to said responsive means when combustion occurs in the chamberfor rendering said operating means effective, whereby the same mayconnect the turbine to the pump to feed further fuel to the motor.

JAMES H. WYLD. LOVELL LAWRENCE, JR.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 1,237,862 Bintlifl Aug. 21, 19171,596,836 Hoff Aug. 17, 1928 1,879,186 Goddard Sept. 27, 1932 2,072,384Schmidt Mar. 2, 1937 2,271,903 Stuckenholt Feb. 3, 1942 2,280,835Lysholm Apr. 28, 1942 2,325,619 Lysholm Aug. 3, 1943 2,397,657 GoddardApr. 2, 1946 FOREIGN PATENTS Number Country Date 522,163 France Mar. 22,1921 157,231 Switzerland Dec. 1, 1932

